Effect of Matrix Chemical Nature on the Properties of Composites for Microwave Absorbers

2013 ◽  
Vol 52 (11) ◽  
pp. 1113-1121 ◽  
Author(s):  
Omar A. Al-Hartomy ◽  
Ahmed A. Al-Ghamdi ◽  
Falleh Al-Salamy ◽  
Nikolay Dishovsky ◽  
Rossitsa Shtarkova ◽  
...  
Author(s):  
Richard R. Shivers

The sinus gland is a neurohemal organ located in the crayfish eyestalk and represents a storage site for neurohormones prior to their release into the circulation. The sinus gland contains 3 classes of dense, membrane-limited granules: 1) granules measuring less than 1000 Å in diameter, 2) granules measuring 1100-1400 Å in diameter, and 3) granules measuring 1500-2000 Å in diameter. Class 3 granules are the most electron-dense of the granules found in the sinus gland, while class 2 granules are the most abundant. Generally, all granules appear to undergo similar changes during release.Release of neurosecretory granules may be initiated by a preliminary fragmentation of the “parent granule” into smaller, less dense vesicles which measure about 350 Å in diameter (V, Figs. 1-3). A decrease in density of the granules prior to their fragmentation has been observed and may reflect a change in the chemical nature of the granule contents.


Author(s):  
Nicholas J Severs

In his pioneering demonstration of the potential of freeze-etching in biological systems, Russell Steere assessed the future promise and limitations of the technique with remarkable foresight. Item 2 in his list of inherent difficulties as they then stood stated “The chemical nature of the objects seen in the replica cannot be determined”. This defined a major goal for practitioners of freeze-fracture which, for more than a decade, seemed unattainable. It was not until the introduction of the label-fracture-etch technique in the early 1970s that the mould was broken, and not until the following decade that the full scope of modern freeze-fracture cytochemistry took shape. The culmination of these developments in the 1990s now equips the researcher with a set of effective techniques for routine application in cell and membrane biology.Freeze-fracture cytochemical techniques are all designed to provide information on the chemical nature of structural components revealed by freeze-fracture, but differ in how this is achieved, in precisely what type of information is obtained, and in which types of specimen can be studied.


1998 ◽  
Vol 08 (PR5) ◽  
pp. Pr5-85-Pr5-89
Author(s):  
P. Sarrazin ◽  
F. Bernard ◽  
G. Calvarin ◽  
J. C. Niepce ◽  
B. Thierry

2020 ◽  
pp. 59-64
Author(s):  
N. I. Kurbanova ◽  
◽  
T. M. Gulieva ◽  
N. Ya. Ischenko ◽  
◽  
...  

The effect of additives of nanofillers (NF) containing nanoparticles (NP) of copper oxide, stabilized by a polymer matrix of maleized polyethylene (MPE), obtained by the mechanochemical method, on the properties of composites based on isotactic polypropylene (PP) and high-pressure polyethylene (PE) was studied by X-ray phase (XRD) and thermogravimetric (TGA) analyzes. The enhancement of strength, deformation, and rheological parameters, as well as the thermo-oxidative stability of the obtained nanocomposites was revealed, which, apparently, is due to the synergistic effect of the interaction of copper-containing nanoparticles with anhydride groups of MPE. It is shown that nanocomposites based on PP/PE/NF can be processed both by pressing and injection molding and extrusion, which expands the scope of its application.


2017 ◽  
Vol 5 (2) ◽  
pp. 20-30
Author(s):  
Zaman Khalil Ibrahim

In this research aluminum matrix composites (AMCs) was reinforced by titanium carbide (TiC) particles and was produced. Powder metallurgy technique (PM) has been used to fabricate AMCs reinforced with various amounts (0%, 4%, 8%, 12%, 16% and 20% volume fraction) of TiC particles to study the effect of different volume fractions on mechanical properties of the Al-TiC composites. Measurements of compression strength and hardness showed that mechanical properties of composites increased with an increase in volume fraction of TiC Particles. Al-20 % vol. TiC composites exhibited the best properties with hardness value (97HRB) and compression strength value (275Mpa).


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